Perfluoroelastomers (elastomeric perfluoropolymers) exhibit outstanding high temperature tolerance and chemical resistance in both the cured and uncured states. These properties are attributable to the stability and inertness of the copolymerized perfluorinated monomer units which form the major portion of the polymer backbone, e.g. tetrafluoroethylene, perfluoro(methyl vinyl)ether, perfluoro(propyl vinyl)ether and others disclosed in U.S. Pat. Nos. 3,467,638; 3,682,872; 4,035,565; 4,281,092; and 4,972,038. Perfluoroelastomers also, however, necessarily contain small quantities of less stable copolymerized cure site monomers and, in addition, many perfluoroelastomers contain reactive end-groups introduced by the use of chain transfer agents or molecular weight regulators during polymerization. Such moieties must have a high degree of reactivity in order to promote effective crosslinking and cure chemistry, but this reactivity inherently renders the polymers more susceptible to degradative chemical reactions, such as oxidation. Consequently, certain physical properties of the polymer, in particular compression set, and high temperature stress/strain properties, are adversely affected.